Around 75,000 people have been evacuated from the centre of the city of Calgary as floodwaters devastated much of Canada's southern province of Alberta, killing three people.

Some 1,300 troops have been deployed in the flood zone. Alberta's premier, Alison Redford, warned that communities downstream of Calgary had not yet felt the full force of the floods, as rivers washed out roads and bridges, soaked homes and turned streets into dirt-brown waterways.

On Friday, the Prime Minister, Stephen Harper, called the level of flooding "stunning" and said officials didn't know if it would get worse.

Chris Scott, director of meteorology at The Weather Network, noted that 8.7 inches, equal to nearly six months of normal rainfall, had fallen in 36 hours near Canmore, 65 miles west of Calgary. "Now all that water is rushing downstream, and that's why the situation is so bad in Calgary. This is an unprecedented flooding event." Environment Canada's forecasters say the rains won't let up until Saturday.